You might hear this spring that in Mokraya Olkhovka village of the Volgograd region there were found strange spherical objects and the first version sounded that they found petrified eggs of a dinosaur! We got a chance to look closer at the interesting finding… They are approximately of the same size – about one meter in the diameter and in the height as well. They consist of silicon, sand and metal so there’s no any connection to dinosaurs … Besides, we may see corrosion on some of them.
Another version: hundreds of millions years ago here was a sea and an active underwater volcano that could produce not only steam but water-insoluble minerals as well. They melted in the volcanic orifice, agglomerated, cooled and sank out.
It’s not a bad idea but it doesn’t explain why these objects have the same spherical shape and are located so close to each other. It turned out that similar objects have already been found in other areas of the Earth, particularly in Kazakhstan and New Zealand. There is a scientific term to such phenomenon – “Concretion”, according to their discription these objects do look like silicon concretion.
Concretion found in the steppe of Kazakhstan.
Konkresi ditemukan di padang rumput Kazakhstan.
These findings are not protected and anyone may ruin them or take with him … Such indifference is still shocking even for this country.
3. New Zealand
If you go down to Koekohe beach in New Zealand you can be sure of a big surprise. In front of you, scattered like enormous marbles from some long abandoned game between giants, are hundreds of giant spherical rocks. Or are they the egg shells of sea-born dragons? The Moeraki boulders present us with a mystery – what are they and how on earth did they get there?
Some are isolated but may occur in clusters. That they are here is the result of three things – erosion, concretion and time. First the waves, inexorable and patient, have pounded the local bedrock for countless millennia. The mudstone on the beach – rock which was originally mud and clay – is slowly but surely eroded. Underneath are the boulders that the mudstone – in its original wet form, helped to form. However, the boulders were not there to begin with – that came later.
Many of the Moeraki boulders give the impression of being completely spherical – and they almost are. They are septarian concretions – a sedimentary rock that has had the space between its inidual grains filled up by minerals which acted like cement. Concretions form inside the layers of mud and clay and are not, as some think, boulders buried over time.
They do, however, tend to form early on in the history of the deposited sediment – it is thought they occur before the rest hardens in to rock. A consequence of concretion is that the resulting boulders are more resistant to the weathering effects of the element. So, when the rest of the sedimentary layers is eroded, the boulder (eventually) appears.
What is significant about these concretions is their size. They are big. While not unique on the planet, some of them are up to a meter in diameter but the majority range from 1.5 to 2.2 meters – that is almost seven feet in diameter. Most of them are almost perfect spheres.
The material responsible for their concretion is a carbonate mineral called calcite. In the center the concretion is sometimes quite weak (perhaps the opposite we might expect) but the exterior is usually the hardest part being made up of sometimes 20% calcite. Not only has the calcite concreted the boulder’s clay and silt – it has replaced a lot of it too.
There are large cracks on the boulders and these are known as septaria. The center of each boulder is hollow and the septaria radiate from there. It is not really known what causes these septaria but they can be filled up by several layers of calcite themselves and sometimes an extremely thin layer of quartz.
The Moeraki boulders date from the Paleocene epoch which translates as the early recent. In geological terms that may well be true, but that means that the boulders are at least fifty six million years old. Our own mammalian ancestors during that epoch were mostly small and rodent like until late on.
As you can imagine, there are many Māori legends concerning these hollow boulders. One says that they are eel baskets that came ashore when a large canoe was sunk. The reality is perhaps stranger than the legend. Yet whenever they get visitors, there always has to be one!
In another source this things formed by cementation, with calcium carbonate being the principal cementing agent They may contain a small nucleus of organic material (a shell or plant fragment). Their spherical form suggests that growth was unconstrained by primary sedimentary structures or fabrics, such as would be the case for more flattened or irregularly shaped concretions.
4. From other places
SPECIMEN ORIGIN: Eden, New York, USA
SPECIMEN ORIGIN: Rockwood, Michigan, USA
SPECIMEN ORIGIN: Yukon Territory, CANADA
Some concretions have unique appearances and are given special names. Some are:
1. Cannon Balls
SPECIMEN LOCATION: Kettle Point, Ontario CANADA Cannon Balls - Kettle Point, Ontario, CANADA
This photo was taken at the Indian Reservation at Kettle Point, Ontario. The shale at the edge of Lake Huron is cracking and eroding away from the cannonball. The Point was named because the cannonballs appear like upside down cooking kettles coming through the shale. Many of the local people have dug up cannonballs from the lake and displayed them as ornaments on the front lawns of their homes.
Photos were taken in Central Australia, north of Alice Springs. Photos show the seashore in southeast New Zealand (South Island). Many cannonballs are emerging and rolling into the sea from the low bluffs to the left of the picture. Note that not all concretions are cannonball shaped.
Septarian nodules are common decorative stones that have been used making objects like bookends, clock faces, spheres, eggs or carvings. In North America, the most recognized septarian nodules come from Utah.
Turtle stones are septarian nodules that look like the backs of turtles. The concretions are more oval in shape - like a turtle, rather than spherical - like a ball. The yellow calcite has "oozed out" between the grey rock material and looks like the markings on the back of a box turtle.
4. Thunder Eggs
Septarian Nodule with Calcite from MOROCCO